Diaphragm valve, substrate processing unit and substrate processing apparatus

ABSTRACT

A first diaphragm adheres to a valve seat thereby closing a passage, and separates from the valve seat thereby opening the passage. A link rod couples a second diaphragm identical in shape to the first diaphragm for opening/closing with the first diaphragm. Therefore, the second diaphragm is mechanically interlocked with the first diaphragm, to compensate for volume change caused in a downstream passage when the first diaphragm is worked. Also when the first diaphragm is rapidly worked, therefore, the second diaphragm immediately compensates for subsequent volume change so that no resist is pulled back to or extruded from the downstream passage. Thus provided is a diaphragm valve capable of stably supplying a solution also when a valve is opened/closed.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a diaphragm valve having an inlet port receiving a fluid and an outlet port discharging the fluid, a substrate processing unit supplying a processing solution such as photoresist (hereinafter simply referred to as “resist”) to a semiconductor substrate, a glass substrate for a liquid crystal display, a glass substrate for a photomask or a substrate for an optical disk (hereinafter simply referred to as “substrate”) for performing resist coating processing or the like through the diaphragm valve and a substrate processing apparatus including the substrate processing unit for performing a series of processing such as photolithography on a substrate.

[0003] 2. Description of the Background Art

[0004] A product such as a semiconductor device or a liquid crystal display is manufactured by performing a series of processing such as cleaning, resist coating, exposure, development, etching, formation of an interlayer dielectric film and thermal processing on a substrate. In general, a substrate processing apparatus including a plurality of processing units such as a coating processing unit and a thermal processing unit performs the series of processing. A transport robot provided in the substrate processing apparatus transports the substrate between the plurality of processing units along prescribed order so that the processing units perform processing on the substrate respectively, thereby progressing the series of substrate processing.

[0005] Among the processing units, a unit supplying a processing solution to the substrate, e.g., the coating processing unit discharging the resist to the substrate generally employs a diaphragm valve of Teflon (registered trade mark) for starting and stopping discharging the resist. This is because the diaphragm valve, more hardly causing dusting resulting from sliding as compared with other valves, is suitable for handling the processing solution supplied to the substrate.

[0006] In general, however, it is problematic to employ a diaphragm valve as a discharge valve, as hereinafter described with reference to FIGS. 14 and 15 showing the structure of a conventional diaphragm valve 100. FIGS. 14 and 15 show states opening and closing a passage respectively.

[0007] The diaphragm valve 100 is provided on an intermediate portion of the path of a pipe 110 for feeding resist. The pipe 110 includes an upstream pipe 110 a communicatively connected to a resist supply source (not shown) and a downstream pipe 110 b communicatively connected to a resist discharge nozzle (not shown). The resist supply source feeds the resist at a prescribed pressure, so that the resist flows from an upstream passage 111 of the upstream pipe 110 a to a downstream passage 112 of the downstream pipe 110 b and is discharged from the resist discharge nozzle in the state shown in FIG. 14. In other words, the diaphragm valve 100 has an inlet port 113 receiving a solution and an outlet port 114 discharging the solution.

[0008] When a leak valve (not shown) is opened to release air from an air pipe 104 in the state shown in FIG. 14, a contracted spring 103 is expanded to downwardly move a piston 102. The lower end of the piston 102 is fixed/connected to a diaphragm 101, which in turn is pressed against a valve seat 105 due to the downward movement of the piston 102 to shift to the state shown in FIG. 15. In the state shown in FIG. 15, the upstream passage 111 and the downstream passage 112 are blocked up so that no resist flows to the downstream passage 112 and the resist discharge nozzle stops discharging the resist.

[0009] When the air pipe 104 feeds air into the diaphragm valve 100 in the state shown in FIG. 15, the piston 102 is upwardly moved against the force of the spring 103. The diaphragm 101 is separated from the valve seat 105 due to the upward movement of the piston 102 so that the upstream passage 111 and the downstream passage 112 communicate with each other (see FIG. 14) and the resist discharge nozzle starts discharging the resist. The diaphragm valve 100 starts and stops discharging the resist in the aforementioned manner.

[0010] When the diaphragm valve 100 is rapidly opened, i.e., when the diaphragm 101 is rapidly separated from the valve seat 105, the volume of the passage in the diaphragm valve 100 is rapidly increased while no resist flows from the upstream passage 111 at this moment, and hence a back flow is instantaneously caused in the downstream passage 112 to pull back the resist from the resist discharge nozzle to the diaphragm valve 100.

[0011] When the diaphragm valve 100 is opened at a low speed, the resist starts to flow out from the upstream passage 111 before influence is exerted by change of the volume of the passage in the diaphragm valve 100, and hence no resist is pulled back from the resist discharge nozzle. While the diaphragm 101 is not sufficiently separated from the valve seat 105, however, a portion of the passage close to the valve seat 105 is so narrow that no sufficient flow rate for discharging the resist is attained but the resist is disadvantageously intermittently fed from the forward end of the discharge nozzle (the so-called dripping).

[0012] When the diaphragm valve 100 is rapidly closed, i.e., when the diaphragm 101 rapidly adheres to the valve seat 105, on the other hand, it follows that the volume of the passage in the diaphragm valve 100 is so rapidly reduced that the resist is extruded from the downstream passage 112 and blown out from the resist discharge nozzle at the moment of closure of the valve 100. When the diaphragm valve 100 is closed at a low speed, no sufficient flow rate for discharging the resist is attained while the portion of the passage close to the valve seat 105 is narrowed similarly to the above, to result in a problem of dripping from the resist discharge nozzle.

[0013] All of the aforementioned phenomena can hinder stable resist supply and cause coating defects. Therefore, it is necessary to prevent the aforementioned phenomena to the utmost by setting the opening/closing speed for the diaphragm valve 100 to a moderate value. However, condition setting for such an optimum speed is extremely delicate and varies with the viscosity of the resist or the situation of the pipe 110, and hence it is extremely difficult to adjust the valve opening/closing speed.

SUMMARY OF THE INVENTION

[0014] The present invention is directed to a diaphragm valve having an inlet port receiving a fluid and an outlet port discharging the fluid.

[0015] According to the present invention, the diaphragm valve comprises an opening/closing diaphragm capable of closing a passage reaching the outlet port from the inlet port by adhering to a valve seat provided on the passage and opening the passage by separating from the valve seat, working part working the opening/closing diaphragm between a closing state closing the passage and an opening state opening the passage and volume change compensation part provided on a side of the passage closer to the outlet port than the opening/closing diaphragm for compensating for volume change caused in a secondary passage of the passage closer to the outlet port than the opening/closing diaphragm when the opening/closing diaphragm is worked.

[0016] Also when the opening/closing diaphragm is rapidly worked, the volume change compensation part immediately compensates for subsequent volume change and no fluid is pulled back to or extruded from the secondary passage, whereby the fluid can consequently be stably supplied in opening/closing of the valve.

[0017] Preferably, the volume change compensation part includes a compensation diaphragm mechanically interlocked with the opening/closing diaphragm for increasing the volume of the secondary passage when the opening/closing diaphragm closes the passage and reducing the volume of the secondary passage when the opening/closing diaphragm opens the passage.

[0018] Also when the opening/closing diaphragm is rapidly worked, the compensation diaphragm interlocked with the opening/closing diaphragm immediately compensates for subsequent volume change and no fluid is pulled back into or extruded from the secondary passage, whereby the fluid can consequently be stably supplied in opening/closing of the valve.

[0019] More preferably, the opening/closing diaphragm and the compensation diaphragm are substantially identical in shape to each other, and the volume change compensation part includes a link rod coupling the opening/closing diaphragm and the compensation diaphragm with each other.

[0020] It follows that the compensation diaphragm is reliably mechanically interlocked with the opening/closing diaphragm, and can correctly compensate for volume change resulting from working of the opening/closing diaphragm.

[0021] According to another aspect of the present invention, the diaphragm valve comprises an opening/closing diaphragm, formed by an elastic member, capable of closing a passage reaching the outlet port from the inlet port by adhering to a valve seat provided on the passage and opening the passage by separating from the valve seat, working part working the opening/closing diaphragm between a closing state closing the passage and an opening state opening the passage, a closed space forming member formed by a member not substantially deformed by a working pressure of the working part working the opening/closing diaphragm for sealing the inner side of the opening/closing diaphragm thereby defining a closed space and an incompressible fluid filling up the closed space.

[0022] Also when the opening/closing diaphragm is rapidly worked, no volume change results in the passage and no fluid is pulled back or extruded, whereby the fluid can consequently be stably supplied in opening/closing of the valve.

[0023] The present invention is also directed to a substrate processing unit supplying a processing solution to a substrate for performing prescribed processing.

[0024] The present invention is further directed to a substrate processing apparatus performing a series of processing consisting of a plurality of steps on a substrate.

[0025] Accordingly, an object of the present invention is to provide a diaphragm valve capable of stably supplying a solution also when the valve is opened/closed as well as a substrate processing unit and a substrate processing apparatus including the same.

[0026] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a plan view showing the overall structure of a substrate processing apparatus according to a first embodiment of the present invention;

[0028]FIG. 2 illustrates the structures of a first processing part group and a second processing part group of the substrate processing apparatus shown in FIG. 1;

[0029]FIG. 3 is a perspective view showing the appearance of a transport robot provided in the substrate processing apparatus shown in FIG. 1;

[0030]FIG. 4 illustrates an exemplary procedure of substrate processing in the substrate processing apparatus shown in FIG. 1;

[0031]FIG. 5 illustrates the structure of a principal part of a coating processing unit provided in the substrate processing unit shown in FIG. 1;

[0032]FIGS. 6 and 7 illustrate an exemplary structure and an exemplary operation of a diaphragm valve according to the present invention;

[0033]FIG. 8 illustrates exemplary change of the flow rate of resist fed from a resist pump to a discharge nozzle;

[0034]FIG. 9 illustrates a resist stop position in the discharge nozzle;

[0035]FIGS. 10 and 11 illustrate the structure and the operation of a diaphragm valve according to a second embodiment of the present invention;

[0036]FIGS. 12 and 13 illustrate the structure and the operation of a diaphragm valve according to a third embodiment of the present invention; and

[0037]FIGS. 14 and 15 illustrate the structure of a conventional diaphragm valve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Embodiments of the present invention are now described in detail with reference to the drawings.

[0039] <1. First Embodiment>

[0040]FIG. 1 is a plan view showing the overall structure of a substrate processing apparatus 1 according to a first embodiment of the present invention. Each of FIG. 1 and subsequent drawings is provided with an X-Y-Z Cartesian coordinate system having a vertical Z-axis and a horizontal X-Y plane at need, in order to clarify the directional relation thereof.

[0041] The substrate processing apparatus 1, performing resist coating processing and development processing on substrates, comprises an indexer ID introducing/discharging the substrates into/from the substrate processing apparatus 1, first and second processing part groups PG1 and PG2 each consisting of a plurality of processing units processing the substrates, an interface IF transferring the substrates between the substrate processing apparatus 1 and an exposure apparatus (stepper: not shown) and a transport robot TR.

[0042] The indexer ID, receiving a carrier (not shown) capable of storing a plurality of substrates and comprising a transfer robot, delivers unprocessed substrates from the carrier to the transport robot TR while receiving processed substrates from the transport robot TR and storing the same in the carrier. The carrier may be an OC (open cassette) exposing the stored substrates to the outside air, an FOUP (front opening unified pod) storing the substrates in a closed space or an SMIF (standard mechanical interface) pod. It is assumed that the carrier stores 25 substrates in this embodiment.

[0043] The interface IF has a function of receiving substrates coated with resist from the transport robot TR and transferring the same to the exposure apparatus (not shown) while receiving exposed substrates from the exposure apparatus and transferring the same to the transport robot TR. The interface IF also has a buffer function of temporarily stocking unexposed and exposed substrates for adjusting transfer timing with respect to the exposure apparatus, and comprises a robot (not shown) transferring the substrates between the exposure apparatus and the transport robot TR and a buffer cassette (not shown) receiving the substrates.

[0044] The substrate processing apparatus 1 comprises a plurality of processing units (processing parts) for processing the substrates, partially forming the first and second processing part groups PG1 and PG2 respectively. FIG. 2 illustrates the structures of the first and second processing part groups PG1 and PG2. The first processing part group PG1 is formed by arranging a plurality of thermal processing units above coating processing units (resist coating processing parts) SC1 and SC2 serving as solution processing units. While FIG. 2 illustrates the processing units in planar arrangement for the convenience of illustration, the same are vertically stacked along the Z-axis direction in practice.

[0045] The coating processing units SC1 and SC2 are the so-called spin coaters supplying photoresist to the main surfaces of the substrates and rotating the substrates thereby homogeneously performing resist coating. A diaphragm valve according to the present invention is built into each of the coating processing units SC1 and SC2, as described later in detail.

[0046] Three columns of thermal processing units stacked in three stages are provided above the coating processing units SC1 and SC2. In other words, the first processing part group PG1 is provided with a column formed by stacking a cooling unit CP1, an adherence reinforcing unit (adherence reinforcing processing part) AH and a heating unit HP1 in ascending order, a column formed by stacking a cooling unit CP2, a heating unit HP2 and a heating unit HP3 in ascending order and a column formed by stacking a cooling unit CP3, a heating unit HP4 and a heating unit HP5 in ascending order respectively.

[0047] Similarly, the second processing part group PG2 is formed by arranging a plurality of thermal processing units above development processing units SD1 and SD2 serving as solution processing units. The development processing units SD1 and SD2 are the so-called spin developers performing development processing by supplying a developer onto the exposed substrates. Three columns of thermal processing units stacked in three stages are provided above the development processing units SD1 and SD2. In other words, the second processing part group PG2 is provided with a column formed by stacking a cooling unit CP4, a post-exposure baking unit PEB and a heating unit HP6 in ascending order, a column formed by stacking a cooling unit CP5, a heating unit HP7 and a heating unit HP8 in ascending order and a column formed by stacking a cooling unit CP6, a heating unit HP9 and a heating unit HP10 in ascending order respectively.

[0048] The heating units HP1 to HP10 are the so-called hot plates heating the substrates and increasing the temperatures thereof to a prescribed level. The adherence reinforcing unit AH and the post-exposure baking unit PEB are also heating units heating the substrates before resist coating processing and immediately after exposure respectively. The cooling units CP1 to CP6 are the so-called cool plates cooling the substrates and reducing the temperatures thereof to a prescribed level while keeping the substrates at the prescribed temperature level.

[0049] Throughout the specification, the processing units (the heating units HP1 to HP10 and the cooling units CP1 to CP6) controlling the temperatures of the substrates are referred to as thermal processing units. Further, the processing units such as the coating processing units SC1 and SC2 and the development processing units SD1 and SD2 supplying processing solutions to the substrates and performing prescribed processing are referred to as solution processing units. The solution processing units and the thermal processing units are generically referred to as processing units.

[0050] Filter fan units FFU are provided immediately under the thermal processing units for forming down flows of clean air managed in temperature and relative humidity on the side of the solution processing units. A further filter fan unit (not shown) is provided also on a position above the transport robot TR for forming a down flow of clean air directed to a transport space.

[0051] The substrate processing apparatus 1 is provided therein with a controller CR formed by a computer consisting of a memory, a CPU and the like. This controller CR controls a transport operation of the transport robot TR according to a prescribed processing program, and supplies instructions to the respective processing units for setting processing conditions.

[0052]FIG. 3 is a perspective view showing the appearance of the transport robot TR. The transport robot TR is provided with an arm stage 35 comprising transport arms 31 a and 31 b on a telescopic body 40, which in turn implements a multistage telescopic structure.

[0053] The telescopic body 40 is formed by four divisional bodies 40 a, 40 b, 40 c and 40 d in descending order. The divisional body 40 a is storable in the divisional body 40 b, which in turn is storable in the divisional body 40 c, which in turn is storable in the divisional body 40 d. The telescopic body 40 is contracted when the divisional bodies 40 a to 40 d are successively stored, while the telescopic body 40 is expanded when the divisional bodies 40 a to 40 d are successively drawn out. In other words, the divisional body 40 a is stored in the divisional body 40 b, which in turn is stored in the divisional body 40 c, which in turn is stored in the divisional body 40 d in contraction of the telescopic body 40. On the other hand, the divisional body 40 a is drawn out from the divisional body 40 b, which in turn is drawn out from the divisional body 40 c, which in turn is drawn out from the divisional body 40 d in expansion of the telescopic body 40.

[0054] A telescopic vertical moving mechanism provided in the telescopic body 40 implements the telescopic operation thereof. The telescopic vertical moving mechanism can be formed by a mechanism driving a combination of a plurality of belts and a plurality of rollers with a motor, for example. The transport robot TR can vertically move the transport arms 31 a and 31 b through this telescopic vertical moving mechanism.

[0055] The transport robot TR can also horizontally reciprocate and rotate the transport arms 31 a and 31 b. More specifically, the arm stage 35 provided on the divisional body 40 a horizontally reciprocates and rotates the transport arms 31 a and 31 b. In other words, the arm stage 35 bends and stretches arm segments of the transport arms 31 a and 31 b respectively thereby horizontally reciprocating the transport arms 31 a and 31 b, while the arm stage 35 itself is rotated with respect to the telescopic body 40 thereby rotating the transport arms 31 a and 31 b.

[0056] Therefore, the transport robot TR can vertically move, rotate and horizontally reciprocate the transport arms 31 a and 31 b. In other words, the transport robot TR can three-dimensionally move the transport arms 31 a and 31 b. The transport arms 31 a and 31 b holding substrates W are three-dimensionally moved to transfer the substrates W between the same and the plurality of processing units, thereby transporting the substrates W to the plurality of processing units for performing various processing on the substrates W.

[0057] The substrate processing procedure in the aforementioned substrate processing apparatus 1 is now described. FIG. 4 illustrates an exemplary substrate processing procedure in the substrate processing apparatus 1. First, an unprocessed substrate W delivered from the indexer ID to the transport robot TR is introduced into the adherence reinforcing unit AH. The adherence reinforcing unit AH serving as the adherence reinforcing processing part heating the substrate W for improving adhesiveness between the substrate W and the resist sprays vaporized HMDS (hexamethyldisilazane) to the heated substrate W thereby reinforcing adhesiveness. Then, the transport robot TR transports the substrate W subjected to the adherence reinforcing processing from the adherence reinforcing unit AH to the cooling unit CP1. The cooling unit CP1 is the cool plate cooling the substrate W heated in the adherence reinforcing unit AH.

[0058] The transport robot TR transports the cooled substrate W from the cooling unit CP1 to the coating processing unit SC1. The coating processing unit SC1 supplies the resist to the main surface of the substrate W and rotates the substrate W for performing resist coating processing. The supplied resist centrifugally spreads on the overall main surface of the substrate W for forming a resist film.

[0059] The transport robot TR transports the substrate W coated with the resist from the coating processing unit SC1 to the heating unit HP1. The heating unit HP1 is the hot plate heating the substrate W coated with the resist by the coating processing unit SC1. This heating is thermal processing, referred to as prebaking, of evaporating an excess solvent component contained in the resist applied to the substrate W, stiffening the adhesiveness between the resist and the substrate W and forming the resist film of stable photosensitivity.

[0060] The transport robot TR transports the prebaked substrate W from the heating unit HP1 to the cooling unit CP2. The cooling unit CP2 cools the prebaked substrate W.

[0061] After termination of the cooling processing, the transport robot TR transports the substrate W from the cooling unit CP2 to the interface IF. The interface IF transfers the substrate W, formed with the resist film, received from the transport robot TR to the exposure apparatus (stepper). The exposure apparatus exposes the substrate W. The exposed substrate W is returned from the exposure apparatus to the interface IF.

[0062] The transport robot TR transports the substrate W returned to the interface IF to the post-exposure baking unit PEB. The post-exposure baking unit PEB performs thermal processing (post-exposure baking) of homogeneously diffusing a product resulting from photochemical reaction in the resist film. Waviness of the resist is eliminated on the boundary between exposed and unexposed portions due to the thermal processing, leading to formation of an excellent pattern.

[0063] The transport robot TR transports the substrate W subjected to post-exposure baking from the post-exposure baking unit PEB to the cooling unit CP3. The cooling unit CP3 cools the substrate W subjected to the post-exposure baking. Thereafter the transport robot TR transports the substrate W from the cooling unit CP3 to the development processing unit SD1. The development processing unit SD1 develops the exposed substrate W.

[0064] The transport robot TR transports the developed substrate W from the development processing unit SD1 to the heating unit HP2. The heating unit HP2 heats the developed substrate W. Thereafter the transport robot TR transports the substrate W from the heating unit HP2 to the cooling unit CP4, which in turn cools the substrate W.

[0065] The transport robot TR returns the substrate W cooled in the cooling unit CP4 to the indexer ID and stores the same in the carrier.

[0066] As hereinabove described, the transport robot TR transports the substrate W according to the procedure shown in FIG. 4, so that the processing units perform a series of processing consisting of resist coating processing, development processing and subsequent thermal processing on the substrate W. Referring to FIG. 4, the coating processing unit SC1 may be replaced with the coating processing unit SC2 having an equivalent function, or the substrate W may be introduced into either one of the coating processing units SC1 and SC2 in the so-called parallel processing. This also applies to the development processing unit SD1, the heating unit HP1, the cooling unit CP1 etc. provided along with other processing units having equivalent functions.

[0067] While the overall structure of the substrate processing apparatus 1 and the outline of the procedure therein have been described, the coating processing unit SC1 provided on the substrate processing apparatus 1 is further described. The following description of the coating processing unit SC1 also applies to the coating processing unit SC2.

[0068]FIG. 5 illustrates the structure of a principal part of the coating processing unit SC1. A spin chuck 41 substantially horizontally holds the substrate W. The spin chuck 41 is the so-called vacuum chuck vacuum-sucking the back surface of the substrate W thereby holding the substrate W. The spin chuck 41 may alternatively be formed by the so-called mechanical chuck mechanically grasping the edge of the substrate W.

[0069] A motor shaft 42 of a motor (not shown) is suspended from the central portion of the lower surface of the spin chuck 41. The motor is driven to normally or oppositely rotate the motor shaft 42 thereby rotating the spin chuck 41 and the substrate W held by the same in a horizontal plane.

[0070] The coating processing unit SC1 is provided with a cup 43 receiving and recovering the resist scattered from the substrate W rotated and coated with the resist. The cup 43, relatively vertically movable with respect to the spin chuck 41, is located around the substrate W held by the spin chuck 41 when the substrate W is coated with the resist, as shown in FIG. 5. In this state, the inner wall surface of the cup 43 receives the resist scattered from the rotated substrate W and guides the same to a lower discharge port (not shown). When the transport robot TR introduces/discharges the substrate W into/from the coating processing unit SC1, the spin chuck 41 projects beyond the upper end of the cup 43.

[0071] In the resist coating processing, a discharge nozzle 45 discharges the resist to the substrate W held by the spin chuck 41 and rotated. The discharge nozzle 45 is communicatively connected with a resist pump 30 serving as a resist supply source through a resist pipe 20. The resist pipe 20 communicatively connecting the resist pump 30 and the discharge nozzle 45 with each other is provided with a filter 37 and a diaphragm valve 10 according to the present invention. The resist pump 30 sucks the resist stored in a resist bottle 36 and feeds the same to the resist pipe 20. The resist fed to the resist pipe 20 is purged through the filter 37. When the diaphragm valve 10 is opened, the purged resist is further guided to the discharge nozzle 45 through the diaphragm valve 10 and discharged toward the rotated substrate W from the discharge nozzle 45.

[0072] An air pipe 47 is communicatively connected to the diaphragm valve 10. The air pipe 47 is branched to a supply pipe 47 a and a leak pipe 47 b. The leak pipe 47 b is provided with a leak valve 49. The supply pipe 47 a is provided with an electromagnetic valve 48 and an air pump 46. The diaphragm valve 10, the structure of which is described later, can be opened by closing the leak valve 49 and opening the electromagnetic valve 48 thereby supplying air from the air pipe 47 to the diaphragm valve 10. On the other hand, the diaphragm valve 10 can be closed by opening the leak valve 49 and closing the electromagnetic valve 48 thereby releasing air from the diaphragm valve 10 through the air pipe 47.

[0073] The aforementioned controller CR is provided with a flow control part 38 and an opening/closing control part 39, which are processing parts implemented by the CPU, provided in the controller CR, running prescribed processing programs. The resist pump 30 has a function of controlling the flow rate of the resist fed to the resist pipe 20, and the flow control part 38 controls the resist pump 30 to set the flow rate of the resist fed to the resist pipe 20 to a prescribed value. The opening/closing control part 39 controls the electromagnetic valve 48 and the leak valve 49 for switching supply and release of air to and from the diaphragm valve 10, thereby controlling opening/closing of the diaphragm valve 10.

[0074]FIGS. 6 and 7 illustrate the structure and the operation of the diaphragm valve 10 according to the present invention. The diaphragm valve 10, provided on an intermediate portion of the path of the resist pipe 20, is formed by serially coupling an upstream pipe 20 a, an opening/closing chamber 11, a connecting pipe 20 c, an auxiliary chamber 21 and a downstream pipe 20 b with each other. Therefore, the diaphragm valve 10 has an inlet port 26 receiving the resist and an outlet port 27 discharging the resist. The upstream pipe 20 a and the downstream pipe 20 b partially form the resist pipe 20 as such.

[0075] An end of the upstream pipe 20 a is communicatively connected to the bottom of the opening/closing chamber 11. The other end of the upstream pipe 20 a is connected to the resist pump 30 (more strictly, to the filter 37). Therefore, the resist fed from the resist pump 30 passes through an upstream passage 25 a in the upstream pipe 20 a and flows into the opening/closing chamber 11.

[0076] The opening/closing chamber 11 formed by a hollow box member is provided therein with a piston 12, a spring 13, a partition 14 and a diaphragm 15. The piston 12 is vertically slidable in the opening/closing chamber 11. The spring 13 is arranged between the upper surface of the piston 12 and the upper inner wall surface of the opening/closing chamber 11.

[0077] The piston 12 passes through the central portion of the partition 14 formed by a flat member vertically partitioning the inner part of the opening/closing chamber 11. While the piston 12 is slidable with respect to the partition 14, contact portions of the piston 12 and the partition 14 are so completely sealed that no air fed from the air pipe 47 into the opening/closing chamber 11 leaks downward beyond the partition 14 (toward the diaphragm 15).

[0078] The peripheral edge of the diaphragm 15 is fixed to the inner wall surface of the opening/closing chamber 11. The diaphragm 15 directly coming into contact with the resist is preferably made of fluororesin such as Teflon (registered trade mark), for example. The central portion of the diaphragm 15 is fixed to the lower end of the piston 12. The central portion of the diaphragm 15 is also fixed to an end of a link rod 23.

[0079] A valve seat 16 is provided on the bottom center of the opening/closing chamber 11. The connecting pipe 20 c communicatively connects the valve seat 16 of the opening/closing chamber 11 and the auxiliary chamber 21 with each other. The link rod 23 is freely inserted in the connecting pipe 20 c. The link rod 23 is arranged along a valve axis Q defining the central axis of the working direction of the diaphragm 15 serving as a valve body.

[0080] A diaphragm 22 is arranged in the auxiliary chamber 21. The peripheral edge of the diaphragm 22 is fixed to the inner wall surface of the auxiliary chamber 21. The diaphragm 22 is identical in material and shape to the diaphragm 15. The other end of the link rod 23 is fixed to the central portion of the diaphragm 22. Therefore, it follows that the diaphragm 22 is provided on the aforementioned valve axis Q, as shown in FIGS. 6 and 7.

[0081] An end of the downstream pipe 20 b is communicatively connected to a portion of the auxiliary chamber 21 located upward beyond the diaphragm 22, i.e., a region receiving the resist. The other end of the downstream pipe 20 b partially forming the resist pipe 20 is communicatively connected to the discharge nozzle 45 as such.

[0082] When the leak valve 49 is closed and the electromagnetic valve 48 is opened in the diaphragm valve 10 having the aforementioned structure, the air pipe 47 supplies air into the opening/closing chamber 11 as shown by arrow AR6 in FIG. 6 for lifting the piston 12 against the elastic force of the spring 13, as shown in FIG. 6. Thus, the diaphragm 15 fixed to the piston 12 is deformed and separated from the valve seat 16. The diaphragm 22, which is identical in shape to the diaphragm 22 and connected thereto by the link rod 23, is deformed absolutely identically to the diaphragm 15 when the piston 12 is lifted.

[0083] When the diaphragm 15 serving as the valve body is separated from the valve seat 16 as shown in FIG. 6, the upstream passage 25 a and the downstream passage 25 b communicate with each other and it follows that the resist fed from the resist pump 30 reaches the discharge nozzle 45 through the upstream passage 25 a and the downstream passage 25 b to be discharged from the discharge nozzle 45 toward the substrate W. In other words, a passage 25 reaching the outlet port 27 from the inlet port 26 is opened in FIG. 6. According to this embodiment, the diaphragm 15 for opening/closing is provided on the passage 25 reaching the outlet port 27 from the inlet port 26, while portions of the passage 25 upstream and downstream the diaphragm 15 define the upstream passage 25 a and the downstream passage 25 b respectively.

[0084] When the electromagnetic valve 48 is closed and the leak valve 49 is opened, no pressure lifts the piston 12 against the restoring force of the spring 13. Therefore, the piston 12 is pushed down due to the restoring force of the spring 13, to extrude air from the opening/closing chamber 11 through the air pipe 47 as shown by arrow AR7 in FIG. 7. When the piston 12 is pushed down, the diaphragm 15 fixed thereto is deformed and adheres to the valve seat 16. The diaphragm 22 is also deformed absolutely identically to the diaphragm 15 when the piston 12 is pushed down, similarly to the above.

[0085] When the diaphragm 15 serving as the valve body adheres to the valve seat 16 as shown in FIG. 7, the upstream passage 25 a and the downstream passage 25 b are so blocked up that the resist fed from the resist pump 30 cannot flow to the downstream passage 25 b and does not reach the discharge nozzle 45. Therefore, the discharge nozzle 45 stops discharging the resist. In other words, the passage 25 reaching the outlet port 27 from the inlet port 26 is closed in FIG. 7.

[0086] Thus, the discharge nozzle 45 starts and stops discharging the resist when the diaphragm 15 for opening/closing is separated from and adheres to the valve seat 16 thereby opening and closing the passage 25 reaching the outlet port 27 from the inlet port 26 respectively. The electromagnetic valve 48, the leak valve 49, the piston 12, the spring 13 etc. function as working means working the diaphragm 15. When the substrate processing apparatus 1 performs the resist coating processing, the opening/closing control part 39 closes the leak valve 49 and opens the electromagnetic valve 48 thereby separating the diaphragm 15 from the valve seat 16 and opening the aforementioned passage 25. When the substrate processing apparatus 1 performs no resist coating processing, the opening/closing control part 39 opens the leak valve 49 and closes the electromagnetic valve 48 thereby bringing the diaphragm 15 into close contact with the valve seat 16 and closing the passage 25.

[0087] As hereinabove described, the operation of the diaphragm 15 results in volume change of the passage 25 reaching the outlet port 27 from the inlet pot 26. The end of the downstream passage 25 b is opened as the discharge nozzle 45 while the resist pump 30 closes the end of the upstream passage 25 a in the passage 25, and hence the downstream passage 25 b is exclusively influenced by the volume change following the operation of the diaphragm 15. In other words, the downstream passage 25 b pulls back and extrudes the resist when the diaphragm 15 is separated from and adheres to the valve seat 16 respectively. Particularly when the diaphragm 15 is rapidly worked by simply opening/closing the electromagnetic valve 48 and the leak valve 49 as in this embodiment, it follows that the pressure for pulling back or extruding the resist strongly functions.

[0088] In this embodiment, therefore, the diaphragm 22 is provided on the portion of the passage 25 closer to the outlet port 27 than the diaphragm 15 for opening/closing. The link rod 23 couples the diaphragm 22 having the same shape as the diaphragm 15 to the diaphragm 15.

[0089] Therefore, the diaphragm 22 is so mechanically interlocked with the diaphragm 15 as to increase the volume of the downstream passage (secondary passage) 25 b when the diaphragm 15 closes the passage 25 by adhering to the valve seat 16. The diaphragm 22 reduces the volume of the downstream passage 25 b when the diaphragm 15 opens the passage 25 by being separated from the valve seat 16. The diaphragm 22 having the same shape as the diaphragm 15 increases/reduces the volume equivalently and oppositely to the volume change following the operation of the diaphragm 15.

[0090] In other words, the diaphragm 22 compensates for the volume change caused in the downstream passage 25 b of the passage 25, i.e., the secondary passage closer to the outlet port 27 than the diaphragm 15, upon the operation of the diaphragm 15.

[0091] Also when the diaphragm 15 is rapidly worked by simply opening/closing the electromagnetic valve 48 and the leak valve 49, therefore, the diaphragm 22 interlocked with the diaphragm 15 immediately compensates for the subsequent volume change so that no resist is pulled back to or extruded from the downstream passage 25 b. Consequently, the resist can be stably supplied also when the diaphragm valve 10 is opened/closed, thereby suppressing a coating defect resulting from unstable resist supply. Further, no mechanism is required for controlling the flow rate of air in the air pipe 47, and the speed for opening/closing the diaphragm valve 10 may not be controlled through a difficult operation.

[0092] Particularly in the first embodiment, the diaphragm 22 for volume compensation is provided on the valve axis Q serving as the central axis of the working direction of the diaphragm 15 and the link rod 23 is arranged along the valve axis Q. Therefore, the diaphragm 22 is provided on the direction along the valve axis Q causing a pressure wave due to the operation of the diaphragm 15 to operate along the direction causing the pressure wave. Therefore, it follows that the diaphragm 22 more effectively absorbs the volume change resulting from the operation of the diaphragm 15.

[0093] As hereinabove described, the flow control part 38 controls the flow rate of the resist fed from the resist pump 30 to the discharge nozzle 45, and the opening/closing control part 39 controls the electromagnetic valve 48 and the leak valve 49 for switching opening/closing of the diaphragm valve 10. FIG. 8 shows exemplary change of the flow rate of the resist fed from the resist pump 30 to the discharge nozzle 45. The flow control part 38 retaining a look-up table shown in FIG. 8 controls the resist pump 30 according to the same for controlling the flow rate of the resist fed from the resist pump 30 to the discharge nozzle 45. When the discharge nozzle 45 stops discharging the resist, the opening/closing control part 39 controls the electromagnetic valve 48 and the leak valve 49 so that the diaphragm 15 closes the passage 25 the moment the flow rate of the resist fed from the resist pump 30 to the discharge nozzle 45 reaches the prescribed value.

[0094] More specifically, the opening/closing control part 39 controls the electromagnetic valve 48 and the leak valve 49 so that the diaphragm 15 closes the passage 25 when the flow rate of the resist changes as shown in FIG. 8 due to the flow control part 38 controlling the resist pump 30 and reaches a value Q1 at a time t1, for example.

[0095] In general, noise, vibration or breakage of the resist pipe 20 itself may be caused by the so-called water hammer action if the diaphragm 15 rapidly closes the passage 25 when the resist flows in the resist pipe 20. When the diaphragm 22 absorbs the volume change resulting from the operation of the diaphragm 15 as in this embodiment, however, the water hammer action can be prevented by relaxing a pressure wave resulting from the diaphragm 15 rapidly closing the passage 25 by volume change caused by the diaphragm 22.

[0096] If the diaphragm 15 closes the passage 25 when the flow rate of the resist fed from the resist pump 30 to the discharge nozzle 45 reaches the prescribed vale, further, no conventional suck-back operation is required. A conventional resist discharge mechanism performs a suck-back operation of sucking resist from a resist pipe and slightly pulling back a solution remaining in the vicinity of the forward end of a discharge nozzle after stopping discharging the resist through a specific mechanism, in order to prevent solution dripping from the forward end of the discharge nozzle.

[0097] When the diaphragm 22 absorbs the volume change resulting from the operation of the diaphragm 15 as in this embodiment, the discharge nozzle 45 can stably stop discharging the resist and a solution of an amount substantially proportionate to the flow rate of the resist at the time of stopping discharging the resist escapes from the forward end of the discharge nozzle 45 due to energy of a flow, whereby an operation similar to the suck-back operation can be performed and the forward end position of the resist can be controlled when stopping discharging the resist.

[0098]FIG. 9 illustrates a resist stop position in the discharge nozzle 45. If the diaphragm 15 closes the passage 25 when the flow rate of the resist fed from the resist pump 30 to the discharge nozzle 45 reaches the value Q1 at the time t1, for example, the forward end of the resist reaches a position L1 upon stoppage of discharge of the resist. If the diaphragm 15 closes the passage 25 when the flow rate of the resist reaches a value Q2 at a time t2, the forward end of the resist reaches a position L2 upon stoppage of discharge of the resist. Similarly, if the diaphragm 15 closes the passage 25 when the flow rate of the resist reaches a value Q3 at a time t3, the forward end of the resist reaches a position L3 upon stoppage of discharge of the resist. Thus, the resist forward end position upon stoppage of discharge is defined in response to the flow rate of the resist fed from the resist pump 30 to the discharge nozzle 45 when the diaphragm 15 closes the passage 25 and the opening/closing control part 39 controls the electromagnetic valve 48 and the leak valve 49 so that the diaphragm 15 closes the passage 25 when the flow rate of the resist reaches the prescribed value, whereby no suck-back operation is required and the resist forward end position upon stoppage of discharge can be adjusted.

[0099] <2. Second Embodiment>

[0100] A diaphragm valve 60 according to a second embodiment of the present invention is now described. The second embodiment is different from the first embodiment in the structure of the diaphragm valve 60, while the remaining portions (e.g., the overall structure and a procedure of a substrate processing apparatus) of the former are identical to those of the latter and hence redundant description is omitted.

[0101]FIGS. 10 and 11 illustrate the structure and the operation of the diaphragm valve 60 according to the second embodiment. Members identical to those of the first embodiment are denoted by the same reference numerals.

[0102] The diaphragm valve 60, provided on an intermediate portion of the path of a resist pipe 20, is formed by serially coupling an upstream pipe 20 a, an opening/closing chamber 61 and a downstream pipe 20 b with each other. Therefore, the diaphragm valve 60 has an inlet port 26 receiving resist and an outlet port 27 discharging the resist.

[0103] An end of the upstream pipe 20 a is communicatively connected to the bottom of the opening/closing chamber 61. A valve seat 16 is formed on a portion of the opening/closing chamber 61 communicatively connected with the upstream pipe 20 a. The other end of the upstream pipe 20 a is connected to a resist pump 30. Therefore, the resist fed from the resist pump 30 flows into the opening/closing chamber 61 through an upstream passage 25 a in the upstream pipe 20 a.

[0104] The opening/closing chamber 61 is provided therein with a piston 12, a spring 13, a partition 64, a diaphragm 15 and another diaphragm 62. The piston 12 and the spring 13 function identically to those in the first embodiment, so that the piston 12 is lifted by air or pushed down by the spring 13 in response to opening/closing states of an electromagnetic valve 48 and a leak valve 49. The diaphragm 15, identical to that in the first embodiment, is separated from the valve seat 16 (see FIG. 10) when the piston 12 is lifted and adheres to the valve seat 16 (see FIG. 11) when the piston 12 is pushed down.

[0105] The partition 64 formed by a flat member vertically partitioning the inner part of the opening/closing chamber 61 partially receives the piston 12 therein. While the piston 12 is slidable with respect to the partition 64, contact portions of the piston 12 and the partition 64 are so completely sealed that no air fed from an air pipe 47 into the opening/closing chamber 61 leaks downward beyond the partition 64 (toward the diaphragm 15) and no oil filling up the clearance between the partition 64 and the diaphragm 15 leaks upward beyond the partition 64.

[0106] According to the second embodiment, the partition 64 is made of a rigid material such as a metal, and not substantially deformed by the pressure of air fed from the air pipe 47 into the opening/closing chamber 61 for separating the diaphragm 15 from the valve seat 16.

[0107] The diaphragm 62 is provided on a portion of the opening/closing chamber 61 closer to the outlet port 27 of a passage 25 than the diaphragm 15. According to the second embodiment, the diaphragm 62 may not be identical in shape to the diaphragm 15. The inner sides of the diaphragms 15 and 62 communicate with each other to define a closed space 65 sealed with the partition 64. This closed space 65 is filled up with the oil serving as an incompressible fluid. The peripheral edges of the diaphragms 15 and 62 are connected with the opening/closing chamber 61 with no clearance so that no oil leaks to the passage 25, as a matter of course.

[0108] When the leak valve 49 is closed and the electromagnetic valve 48 is opened in the structure of the diaphragm valve 60 according to the second embodiment, the air pipe 47 supplies air into the opening/closing chamber 61 as shown by arrow AR10 in FIG. 10, to lift the piston 12 against the elastic force of the spring 13 as shown in FIG. 10. When the piston 12 is lifted, the diaphragm 15 fixed thereto is deformed and separated from the valve seat 16. At this time, the inner part of the closed space 65 is completely sealed and filled up with the oil serving as the incompressible fluid, whereby it follows that the volume in the closed space 65 is maintained as such. When the diaphragm 15 is inwardly deformed while maintaining the volume in the closed space 65, the diaphragm 62 is hydraulically deformed outward (toward the passage 25). The quantities of volume change by the diaphragms 15 and 62 are equal to each other, and it follows that the diaphragm 62 reduces the volume of the passage 25 increased by the diaphragm 15.

[0109] When the diaphragm 15 serving as a valve body is separated from the valve seat 16 as shown in FIG. 10, the upstream passage 25 a and a downstream passage 25 b communicate with each other and it follows that the resist fed from the resist pump 30 reaches a discharge nozzle 45 through the upstream passage 25 a and the downstream passage 25 b to be discharged from the discharge nozzle 45 toward a substrate W. In other words, the passage 25 reaching the outlet port 27 from the inlet port 26 is opened in FIG. 10. Also in the second embodiment, the diaphragm 15 for opening/closing is provided on the passage 25 reaching the outlet port 27 from the inlet port 26, while portions of the passage 25 upstream and downstream the diaphragm 15 define the upstream passage 25 a and the downstream passage 25 b respectively.

[0110] When the electromagnetic valve 48 is closed and the leak valve 49 is opened, no pressure lifts the piston 12 against the restoring force of the spring 13. Therefore, the piston 12 is pushed down by the restoring force of the spring 13 to extrude air from the opening/closing chamber 61 through the air pipe 47 as shown by arrow AR11 in FIG. 11. When the piston 12 is pushed down, the diaphragm 15 fixed thereto is deformed to adhere to the valve seat 16. When the diaphragm 15 is outwardly deformed while maintaining the volume in the closed space 65 similarly to the above, the diaphragm 62 is hydraulically deformed inward (toward the closed space 65). The quantities of volume change by the diaphragms 15 and 62 are equal to each other, and it follows that the diaphragm 62 increases the volume of the passage 25 reduced by the diaphragm 15.

[0111] When the diaphragm 15 serving as the valve body adheres to the valve seat 16 as shown in FIG. 11, the upstream passage 25 a and the downstream passage 25 b are so blocked up that the resist fed from the resist pump 30 cannot flow to the downstream passage 25 b and does not reach the discharge nozzle 45. Therefore, the discharge nozzle 45 stops discharging the resist. In other words, the passage 25 reaching the outlet port 27 from the inlet port 26 is closed in FIG. 11.

[0112] Thus, the discharge nozzle 45 starts and stops discharging the resist when the diaphragm 15 for opening/closing is separated from and adheres to the valve seat 16 thereby opening and closing the passage 25 reaching the outlet port 27 from the inlet port 26 respectively also in the second embodiment. The electromagnetic valve 48, the leak valve 49, the piston 12, the spring 13 etc. function as working means working the diaphragm 15. When the substrate processing apparatus performs resist coating processing, an opening/closing control part 39 closes the leak valve 49 and opens the electromagnetic valve 48 thereby separating the diaphragm 15 from the valve seat 16 and opening the aforementioned passage 25. When the substrate processing apparatus performs no resist coating processing, the opening/closing control part 39 opens the leak valve 49 and closes the electromagnetic valve 48 thereby bringing the diaphragm 15 into close contact with the valve seat 16 and closing the passage 25.

[0113] Also in the second embodiment, the operation of the diaphragm 15 results in volume change of the passage 25 reaching the outlet port 27 from the inlet pot 26. An end of the downstream passage 25 b is opened as the discharge nozzle 45 while the resist pump 30 closes an end of the upstream passage 25 a in the passage 25, and hence the downstream passage 25 b is exclusively influenced by the volume change following the operation of the diaphragm 15. In other words, the downstream passage 25 b pulls back and extrudes the resist when the diaphragm 15 is separated from and adheres to the valve seat 16 respectively.

[0114] According to the second embodiment, the diaphragm 62 is provided on the portion of the passage 25 closer to the outlet port 27 than the diaphragm 15 for opening/closing. As hereinabove described, the inner sides of the diaphragms 15 and 62 communicate with each other to define the closed space 65 sealed with the partition 64, which is filled up with the oil serving as the incompressible fluid.

[0115] Therefore, the diaphragm 62 is so mechanically interlocked with the diaphragm 15 as to increase the volume of the downstream passage (secondary passage) 25 b when the diaphragm 15 closes the passage 25 by adhering to the valve seat 16. The diaphragm 62 reduces the volume of the downstream passage 25 b when the diaphragm 15 opens the passage 25 by being separated from the valve seat 16. Further, the closed space 65 is filled up with the oil serving as the incompressible fluid, whereby the quantities of volume change by the diaphragms 15 and 62 are equal to each other, and the diaphragm 62 increases/reduces the volume absolutely equivalently and oppositely to the volume change following the operation of the diaphragm 15.

[0116] In other words, the diaphragm 62 operates to compensate for volume change caused in the downstream passage 25 b serving as the secondary passage of the passage 25 closer to the outlet port 27 than the diaphragm 15 when the diaphragm 15 operates.

[0117] Also when the diaphragm 15 is rapidly worked by simply opening/closing the electromagnetic valve 48 and the leak valve 49, therefore, the diaphragm 62 interlocked with the diaphragm 15 immediately compensates for the subsequent volume change so that no resist is pulled back to or extruded from the downstream passage 25 b. Consequently, the resist can be stably supplied also when the diaphragm valve 60 is opened/closed, thereby suppressing a coating defect resulting from unstable resist supply. Further, no mechanism is required for controlling the flow rate of air in the air pipe 47, and the speed for opening/closing the diaphragm valve 60 may not be controlled through a difficult operation.

[0118] Particularly in the second embodiment, the diaphragms 15 and 62 are interlocked with each other through the oil serving as the incompressible fluid filling up the closed space 65 and the volume of the oil is regularly constant, whereby the diaphragm 62 can reliably compensate for volume change resulting from the operation of the diaphragm 15 also when the material or the shape of the diaphragm 62 is different from that of the diaphragm 15. Therefore, it follows that the degree of freedom in design of the diaphragm 60 is improved.

[0119] Further, the closed space 65 of the diaphragm valve 60 according to the second embodiment stores no air, whereby the diaphragm 62 can reliably compensate for the volume change.

[0120] <3. Third Embodiment>

[0121] A diaphragm valve 70 according to a third embodiment of the present invention is now described. The third embodiment is different from the first embodiment in the structure of the diaphragm valve 70, while the remaining portions (e.g., the overall structure and a procedure of a substrate processing apparatus) of the former are identical to those of the latter and hence redundant description is omitted.

[0122]FIGS. 12 and 13 illustrate the structure and the operation of the diaphragm valve 70 according to the third embodiment. Members identical to those of the first embodiment are denoted by the same reference numerals.

[0123] The diaphragm valve 70, provided on an intermediate portion of the path of a resist pipe 20, is formed by serially coupling an upstream pipe 20 a, an opening/closing chamber 71 and a downstream pipe 20 b with each other. Therefore, the diaphragm valve 70 has an inlet port 26 receiving resist and an outlet port 27 discharging the resist.

[0124] An end of the upstream pipe 20 a is communicatively connected to the bottom of the opening/closing chamber 71. A valve seat 16 is formed on a portion of the opening/closing chamber 71 communicatively connected with the upstream pipe 20 a. The other end of the upstream pipe 20 a is connected to a resist pump 30. Therefore, the resist fed from the resist pump 30 flows into the opening/closing chamber 71 through an upstream passage 25 a in the upstream pipe 20 a.

[0125] The opening/closing chamber 71 is provided therein with a piston 12, a spring 13, a partition 74 and a diaphragm 75. The piston 12 and the spring 13 function identically to those in the first embodiment, so that the piston 12 is lifted by air or pushed down by the spring 13 in response to opening/closing states of an electromagnetic valve 48 and a leak valve 49.

[0126] The partition 74 formed by a flat member vertically partitioning the inner part of the opening/closing chamber 71 partially receives the piston 12 therein. While the piston 12 is slidable with respect to the partition 74, contact portions of the piston 12 and the partition 74 are so completely sealed that no air fed from an air pipe 47 into the opening/closing chamber 71 leaks downward beyond the partition 74 (toward the diaphragm 15) and no oil filling up the clearance between the partition 74 and the diaphragm 75 leaks upward beyond the partition 74.

[0127] According to the third embodiment, the partition 74 is made of a rigid material such as a metal and not substantially deformed by the pressure of the air fed from the air pipe 47 into the opening/closing chamber 71 for separating the diaphragm 75 from the valve seat 16.

[0128] The peripheral edge of the diaphragm 75 is fixed to the lower surface of the partition 74. The central portion of the diaphragm 75 is fixed to the lower end of the piston 12. Therefore, the diaphragm 75 is separated from the valve seat 16 as shown in FIG. 12 when the piston 12 is lifted, and adheres to the valve seat 16 when the piston 12 is pushed down as shown in FIG. 13.

[0129] The diaphragm 75 is preferably made of a material prepared by coating the surface, closer to a passage 25, of an elastic member of rubber or the like with fluororesin. The inner side of the diaphragm 75 defines a closed space 76 sealed with the partition 74. The closed space 76 is filled up with oil serving as an incompressible fluid. The peripheral edge of the diaphragm 75 is connected to the partition 74 with no clearance so that no oil leaks to the passage 25, as a matter of course.

[0130] When the leak valve 49 is closed and the electromagnetic valve 48 is opened in the structure of the diaphragm valve 70 according to the third embodiment, the air pipe 47 supplies air into the opening/closing chamber 71 as shown by arrow AR12 in FIG. 12 to lift the piston 12 against the elastic force of the spring 13 as shown in FIG. 12. When the piston 12 is lifted, the diaphragm 75 fixed thereto is deformed and separated from the valve seat 16. At this time, the closed space 76 is completely sealed and filled up with the oil serving as the incompressible fluid, whereby it follows that the volume of the closed space 76 is maintained as such. When the piston 12 is lifted while maintaining the volume of the closed space 76, a portion, not fixed to the piston 12, of the diaphragm 75 formed by the elastic member is hydraulically swollen outward toward the passage 25. The quantities of volume change of the diaphragm 75 resulting from the lifted piston 12 and volume change of the hydraulically swollen diaphragm 75 are canceled and it follows that the passage 25 causes no volume change also when the diaphragm 75 is separated from the valve seat 16.

[0131] When the diaphragm 75 serving as a valve body is separated from the valve seat 16 as shown in FIG. 12, the upstream passage 25 a and the downstream passage 25 b communicate with each other and it follows that the resist fed from the resist pump 30 reaches a discharge nozzle 45 through the upstream passage 25 a and the downstream passage 25 b to be discharged from the discharge nozzle 45 toward a substrate W. In other words, the passage 25 reaching the outlet port 27 from the inlet port 26 is opened in FIG. 12. Also in the third embodiment, the diaphragm 75 for opening/closing is provided on the passage 25 reaching the outlet port 27 from the inlet port 26, while portions of the passage 25 upstream and downstream the diaphragm 75 define the upstream passage 25 a and the downstream passage 25 b respectively.

[0132] When the electromagnetic valve 48 is closed and the leak valve 49 is opened, no pressure lifts the piston 12 against the restoring force of the spring 13. Therefore, the piston 12 is pushed down by the restoring force of the spring 13 to extrude air from the opening/closing chamber 71 through the air pipe 47 as shown by arrow AR13 in FIG. 13. When the piston 12 is pushed down, the diaphragm 75 fixed thereto is deformed to adhere to the valve seat 16. When the piston 12 is pushed down while maintaining the volume in the closed space 76 similarly to the above, the portion, not fixed to the piston 12, of the diaphragm 75 formed by the elastic member is hydraulically depressed inward toward the partition 74. The quantities of volume change of the diaphragm 75 resulting from the downward movement of the piston 12 and volume change of the hydraulically depressed diaphragm 75 are canceled and it follows that the passage 25 causes no volume change also when the diaphragm 75 adheres to the valve seat 16.

[0133] When the diaphragm 75 serving as the valve body adheres to the valve seat 16 as shown in FIG. 13, the upstream passage 25 a and the downstream passage 25 b are so blocked up that the resist fed from the resist pump 30 cannot flow to the downstream passage 25 b and does not reach the discharge nozzle 45. Therefore, the discharge nozzle 45 stops discharging the resist. In other words, the passage 25 reaching the outlet port 27 from the inlet port 26 is closed in FIG. 13.

[0134] Thus, the discharge nozzle 45 starts and stops discharging the resist when the diaphragm 75 for opening/closing is separated from and adheres to the valve seat 16 thereby opening and closing the passage 25 reaching the outlet port 27 from the inlet port 26 respectively also in the third embodiment. The electromagnetic valve 48, the leak valve 49, the piston 12, the spring 13 etc. function as working means working the diaphragm 75. When the substrate processing apparatus performs resist coating processing, an opening/closing control part 39 closes the leak valve 49 and opens the electromagnetic valve 48 thereby separating the diaphragm 75 from the valve seat 16 and opening the aforementioned passage 25. When the substrate processing apparatus performs no resist coating processing, the opening/closing control part 39 opens the leak valve 49 and closes the electromagnetic valve 48 thereby bringing the diaphragm 75 into close contact with the valve seat 16 and closing the passage 25.

[0135] According to the third embodiment, as hereinabove described, the passage 25 causes no volume change due to the operation of the diaphragm 75. In other words, the inner side of the diaphragm 75 defines the closed space 76 sealed with the partition 74, which is filled up with the oil serving as the incompressible fluid. Therefore, the volume of the closed space 76 remains regularly constant and the passage 25 causes no volume change however the diaphragm 75 operates.

[0136] Also when the diaphragm 75 is rapidly worked by simply opening/closing the electromagnetic valve 48 and the leak valve 49, therefore, the passage 25 causes no volume change and no resist is pulled back to or extruded from the downstream passage 25 b. Consequently, the resist can be stably supplied also when the diaphragm valve 70 is opened/closed, thereby suppressing a coating defect resulting from unstable resist supply. Further, no mechanism is required for controlling the flow rate of air in the air pipe 47, and the speed for opening/closing the diaphragm valve 70 may not be controlled through a difficult operation.

[0137] Particularly in the third embodiment, the closed space 76 is filled up with the oil serving as the incompressible fluid thereby implementing functions equivalent to those in the first and second embodiments with the single diaphragm 75. Therefore, the structure of the diaphragm valve 70 can be further simplified.

[0138] Further, the closed space 76 of the diaphragm valve 70 according to the third embodiment stores no air, whereby the diaphragm valve 70 can reliably compensate for the volume change.

[0139] <4. Modifications>

[0140] While the embodiments of the present invention have been described, the present invention is not restricted to the aforementioned embodiments. For example, while each of the aforementioned embodiments employs air, the piston 12, the spring 13 etc. for working the diaphragm 15 (75) for opening/closing, the present invention is not restricted to this but the diaphragm 15 (75) for opening/closing may be worked by an actuator or the like, for example. If the speed for working the diaphragm 15 (75) is slow, however, the passage 25 is instantaneously narrowed in the vicinity of the valve seat 16, no sufficient flow rate of the resist is attained and the aforementioned problem of dripping from the discharge nozzle 45 is caused. Therefore, the actuator can preferably obtain a certain degree of working speed.

[0141] While the resist pump 30 itself has the function of controlling the flow rate of the resist fed to the resist pipe 20 in the first embodiment, a mass flow controller controlling the flow rate of the resist may alternatively be provided independently of the resist pump 30 so that the flow control part 38 controls the mass flow controller.

[0142] While each of the aforementioned second and third embodiments employs oil as the incompressible fluid, the present invention is not restricted to this but another incompressible fluid such as water, for example, may alternatively be employed.

[0143] While the aforementioned first embodiment mechanically interlocks the two diaphragms 15 and 22 with the link rod 23 and the second embodiment mechanically interlocks the two diaphragms 15 and 62 with oil, the present invention is not restricted to these but any mechanism is employable so far as the same is a link mechanism capable of compensating for volume change caused in the downstream passage 25 b when the diaphragm 15 for opening/closing operates.

[0144] While the inner side of the diaphragm 75 defines the closed space 76 sealed with the partition 74 and this closed space 76 is filled up with the oil serving as the incompressible fluid in the third embodiment, a substance having incompressibility and deformability, such as a gel substance wrapped with a fluororesin film, for example, may alternatively be employed as a diaphragm stuck to the partition 74. The passage 25 causes no volume change by any operation of the diaphragm in this case, and hence an effect similar to that of the third embodiment can be attained.

[0145] While the diaphragm valve according to the present invention is built into the resist discharge mechanism of the coating processing unit in each of the aforementioned embodiments, the present invention is not restricted to this but the inventive diaphragm valve may alternatively be built into a substrate processing unit discharging another processing solution such as polyimide, a developer or deionized water for rinsing, for example, to a substrate. Particularly when the inventive diaphragm valve is built into a deionized water discharge mechanism of a cleaning processing unit discharging deionized water to a substrate for cleaning the substrate, the following effect is attained:

[0146] A conventional cleaning processing unit gradually closes a valve upon termination of cleaning processing to gradually weaken discharge of deionized water from a deionized discharge nozzle and hence the locus of the discharged deionized water necessarily passes through an edge of a substrate. Therefore, mist of the deionized water formed when passing through the edge reaches the back surface of the substrate to result in a new contamination source. When the valve is abruptly closed in order to prevent this, a water hammer action may be caused.

[0147] If the inventive diaphragm valve is built into the deionized water discharge mechanism of the cleaning processing unit, the water hammer action can be suppressed as described above also when the diaphragm valve is abruptly closed. When abruptly closing the diaphragm valve while discharging the deionized water from the discharge nozzle at a flow rate exceeding a prescribed value, therefore, it is possible to prevent the locus of the discharged deionized water from passing through the edge of the substrate while suppressing the water hammer action so that no mist of the deionized water reaches the back surface of the substrate.

[0148] While the invention has been shown and described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is therefore understood that numerous modifications and variations can be devised without departing from the scope of the invention. 

What is claimed is:
 1. A diaphragm valve having an inlet port receiving a fluid and an outlet port discharging said fluid, comprising: an opening/closing diaphragm capable of closing a passage reaching said outlet port from said inlet port by adhering to a valve seat provided on said passage and opening said passage by separating from said valve seat; a working part working said opening/closing diaphragm between a closing state closing said passage and an opening state opening said passage; and a volume change compensation part provided on a side of said passage closer to said outlet port than said opening/closing diaphragm for compensating for volume change caused in a secondary passage of said passage closer to said outlet port than said opening/closing diaphragm when said opening/closing diaphragm is worked.
 2. The diaphragm valve according to claim 1, wherein said volume change compensation part includes a compensation diaphragm mechanically interlocked with said opening/closing diaphragm for increasing the volume of said secondary passage when said opening/closing diaphragm closes said passage and reducing the volume of said secondary passage when said opening/closing diaphragm opens said passage.
 3. The diaphragm valve according to claim 2, wherein said opening/closing diaphragm and said compensation diaphragm are substantially identical in shape to each other, and said volume change compensation part includes a link rod coupling said opening/closing diaphragm and said compensation diaphragm with each other.
 4. The diaphragm valve according to claim 3, wherein said compensation diaphragm is provided on a valve axis along which said opening/closing diaphragm works, and said link rod is arranged along said valve axis.
 5. The diaphragm valve according to claim 2, wherein said volume change compensation part includes: a closed space forming member formed by a member not substantially deformed by a working pressure of said working part working said opening/closing diaphragm for sealing the inner side of said opening/closing diaphragm and the inner side of said compensation diaphragm while communicatively interconnecting the same with each other thereby defining a closed space, and an incompressible fluid filling up said closed space.
 6. A diaphragm valve having an inlet port receiving a fluid and an outlet port discharging said fluid, comprising: an opening/closing diaphragm, formed by an elastic member, capable of closing a passage reaching said outlet port from said inlet port by adhering to a valve seat provided on said passage and opening said passage by separating from said valve seat; a working part working said opening/closing diaphragm between a closing state closing said passage and an opening state opening said passage; a closed space forming member formed by a member not substantially deformed by a working pressure of said working part working said opening/closing diaphragm for sealing the inner side of said opening/closing diaphragm thereby defining a closed space; and an incompressible fluid filling up said closed space.
 7. A substrate processing unit supplying a processing solution to a substrate for performing prescribed processing, comprising: a) a holding part holding said substrate; b) a discharge nozzle discharging said processing solution to said substrate held by said holding part; c) a feed source feeding said processing solution to said discharge nozzle; d) a pipe communicatively connecting said feed source and said discharge nozzle with each other for guiding said processing solution from said feed source to said discharge nozzle; and e) a diaphragm valve provided on an intermediate portion of the path of said pipe, said diaphragm valve comprising: e-1) an inlet port receiving said processing solution, e-2) an outlet port discharging said processing solution, e-3) an opening/closing diaphragm capable of closing a passage reaching said outlet port from said inlet port by adhering to a valve seat provided on said passage and opening said passage by separating from said valve seat, e-4) a working part working said opening/closing diaphragm between a closing state closing said passage and an opening state opening said passage, and e-5) a volume change compensation part provided on a side of said passage closer to said outlet port than said opening/closing diaphragm for compensating for volume change caused in a secondary passage of said passage closer to said outlet port than said opening/closing diaphragm when said opening/closing diaphragm is worked.
 8. The substrate processing unit according to claim 7, wherein said volume change compensation part includes a compensation diaphragm mechanically interlocked with said opening/closing diaphragm for increasing the volume of said secondary passage when said opening/closing diaphragm closes said passage and reducing the volume of said secondary passage when said opening/closing diaphragm opens said passage.
 9. The substrate processing unit according to claim 8, wherein said opening/closing diaphragm and said compensation diaphragm are substantially identical in shape to each other, and said volume change compensation part includes a link rod coupling said opening/closing diaphragm and said compensation diaphragm with each other.
 10. The substrate processing unit according to claim 9, wherein said compensation diaphragm is provided on a valve axis along which said opening/closing diaphragm works, and said link rod is arranged along said valve axis.
 11. The substrate processing unit according to claim 8, wherein said volume change compensation part includes: a closed space forming member formed by a member not substantially deformed by a working pressure of said working part working said opening/closing diaphragm for sealing the inner side of said opening/closing diaphragm and the inner side of said compensation diaphragm while communicatively interconnecting the same with each other thereby forming a closed space, and an imcompressible fluid filling up said closed space.
 12. The substrate processing unit according to claim 7, further comprising: f) a flow control part controlling the flow rate of said processing solution fed from said feed source to said discharge nozzle, and g) an opening/closing control part controlling said working part so that said opening/closing diaphragm enters said closing state when the flow rate of said processing solution fed from said feed source to said discharge nozzle reaches a prescribed value as said discharge nozzle stops discharging said processing solution.
 13. The substrate processing unit according to claim 12, wherein said processing solution is photoresist.
 14. A substrate processing apparatus performing a series of processing consisting of a plurality of steps on a substrate, comprising: a) a coating processing unit, performing resist coating processing on said substrate, comprising: a-1) a holding part holding said substrate, a-2) a discharge nozzle discharging photoresist to said substrate held by said holding part, a-3) a feed source feeding said photoresist to said discharge nozzle, a-4) a pipe communicatively connecting said feed source and said discharge nozzle with each other for guiding said photoresist from said feed source to said discharge nozzle, and a-5) a diaphragm valve, provided on an intermediate portion of the path of said pipe, comprising: a-5-1) an inlet port receiving said photoresist, a-5-2) an outlet port discharging said photoresist, a-5-3) an opening/closing diaphragm capable of closing a passage reaching said outlet port from said inlet port by adhering to a valve seat provided on said passage and opening said passage by separating from said valve seat, a-5-4) a working part working said opening/closing diaphragm between a closing state closing said passage and an opening state opening said passage, and a-5-5) a volume change compensation part provided on a side of said passage closer to said outlet port than said opening/closing diaphragm for compensating for volume change caused in a secondary passage of said passage closer to said outlet port than said opening/closing diaphragm when said opening/closing diaphragm is worked; b) a development processing unit developing said substrate; c) a thermal processing unit thermally processing said substrate; and d) a transport part transporting said substrate between respective said processing units.
 15. The substrate processing apparatus according to claim 14, wherein said volume change compensation part includes a compensation diaphragm mechanically interlocked with said opening/closing diaphragm for increasing the volume of said secondary passage when said opening/closing diaphragm closes said passage and reducing the volume of said secondary passage when said opening/closing diaphragm opens said passage.
 16. The substrate processing apparatus according to claim 15, wherein said opening/closing diaphragm and said compensation diaphragm are substantially identical in shape to each other, and said volume change compensation part includes a link rod coupling said opening/closing diaphragm and said compensation diaphragm with each other.
 17. The substrate processing apparatus according to claim 16, wherein said compensation diaphragm is provided on a valve axis along which said opening/closing diaphragm works, and said link rod is arranged along said valve axis.
 18. The substrate processing apparatus according to claim 15, wherein said volume change compensation part includes: a closed space forming member formed by a member not substantially deformed by a working pressure of said working part working said opening/closing diaphragm for sealing the inner side of said opening/closing diaphragm and the inner side of said compensation diaphragm while communicatively interconnecting the same with each other thereby defining a closed space, and an incompressible fluid filling up said closed space.
 19. The substrate processing apparatus according to claim 14, wherein said coating processing unit further comprises: a-6) a flow control part controlling the flow rate of said photoresist fed from said feed source to said discharge nozzle, and a-7) an opening/closing control part controlling said working part so that said opening/closing diaphragm enters said closing state when the flow rate of said photoresist fed from said feed source to said discharge nozzle reaches a prescribed value as said discharge nozzle stops discharging said photoresist.
 20. The substrate processing apparatus according to claim 14, further comprising: e) an indexer transferring an unprocessed substrate to said transport part while receiving a processed substrate from said transport part, and f) an interface transferring a substrate between an exposure unit provided outside said apparatus and said transport part. 